Post-deploy abra.sh hooks (!292)

This solves coop-cloud/organising#235

Co-authored-by: Moritz <moritz.m@local-it.org>
Reviewed-on: coop-cloud/abra#292

cli/app/upgrade.go

@@ -205,6 +205,14 @@ recipes.
 			logrus.Fatal(err)
 		}
 
+		postDeployCmds, ok := app.Env["POST_UPGRADE_CMDS"]
+		if ok && !internal.DontWaitConverge {
+			logrus.Debugf("run the following post-deploy commands: %s", postDeployCmds)
+			if err := internal.PostCmds(cl, app, postDeployCmds); err != nil {
+				logrus.Fatalf("attempting to run post deploy commands, saw: %s", err)
+			}
+		}
+
 		return nil
 	},
 	BashComplete: autocomplete.AppNameComplete,